Pressure sensors with spaced apart capacitive electrodes are previously known. U.S. Pat. No. 4,227,419 discloses a capacitive pressure sensor with a pair of spaced apart ceramic plates with opposed flat faces on which electrodes are disposed. At least one of the ceramic plates is sufficiently flexible to provide a diaphragm which flexes with variations in pressure applied thereto to change the capacitance of the capacitor formed by the electrodes. Suitable electronic circuitry utilizes the change in capacitance to produce an output signal indicative of the pressure applied to the diaphragm. The ceramic plates are secured and sealed together in spaced apart relationship adjacent their periphery by a glass frit disposed between them and fired to fuse them together. Usually, the sealed space between the ceramic plates is evacuated and frequently filled with a gaseous controlled atmosphere.